In Summary
  • There are two types of fruits on the basis of ripening. Fruits that ripen after harvesting at maturity are known as climacteric and fruits that will not ripen after harvesting even at maturity, are known as non-climacteric.
  • Non-climacteric fruits have to be allowed to ripen while still attached to the plant. The best known non-climacteric fruits are citrus and the pineapple.
  • The period between harvesting and the onset of ripening can be contracted through addition of exogenous ethylene to shorten the ripening period.
  • With this process, ripening is instantaneous. The gassing process takes between 20—24 hours, mostly depending on the temperature.

There has been concern over the fruit ripening process, especially when it comes to the artificially ripened fruits.

This is a valid concern not only in Kenya but also globally, as fruits are consumed best when they are ripe, with the exception of a few ones like apples and some varieties of pears.

For proper ripening, most fruits are harvested mature-green, when physiological growth, which refers to cell division, cell multiplication and cell differentiation, is complete.

Thanks to recent advances in technology, it is now possible to hasten the ripening of fruits using ethylene, a hormone produced naturally or by the combustion of gases.

It is, however, important to note that ripening does not refer only to change in colour, usually from green to yellow to red or even black, depending on the fruit, as commonly understood. Colour change just happens to be the main apparent indicator of ripening.

There are two types of fruits on the basis of ripening. Fruits that ripen after harvesting at maturity are known as climacteric and fruits that will not ripen after harvesting even at maturity, are known as non-climacteric.

Non-climacteric fruits have to be allowed to ripen while still attached to the plant. The best known non-climacteric fruits are citrus and the pineapple.

Most of all the other commonly eaten fruits are climacteric and this group includes the banana, mango, passion fruit, papaya, avocado and the tomato.

When climacteric fruits are harvested, two things are very important. The system that ensures protection from attack by pests when attached to the plant is curtailed, making the fruits more vulnerable.

Secondly, the fruit is still living and continues with respiration, which finally leads to ripening at nominal rate for some time after which the rate increases tremendously and heralds the onset of ripening.

Thereafter, the ripening is automatic and takes only a day or two. The increase in respiration is paralleled by the production of ethylene, a ripening hormone produced naturally by plants such as apples, avocados, bananas, melons, peaches, pears, and tomatoes.

Ethylene can, however, be produced artificially through the combustion of gases.

The period between harvesting and the onset of ripening can be contracted through addition of exogenous ethylene to shorten the ripening period.

Ethylene is a growth/maturity hormone, which is naturally produced by all vegetative plants. Under normal temperatures and pressures, ethylene exists in gaseous form. Maturity and, therefore, ripening of non-climacteric fruits is enhanced by spraying in the field.

UNDERGROUND PIT

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